Re: ktrace on NFSroot failing?
John Baldwin wrote: > On 3/10/22 8:14 AM, Mateusz Guzik wrote: >> On 3/10/22, Bjoern A. Zeeb wrote: >>> Hi, >>> >>> I am having a weird issue with ktrace on an nfsroot machine: >>> >>> root:/tmp # ktrace sleep 1 >>> root:/tmp # kdump >>> -559038242 Events dropped. >>> kdump: bogus length 0xdeadc0de >>> >>> Anyone seen something like this before? >>> >> >> I just did a quick check and it definitely fails on nfs mounts: >> # ktrace pwd >> /root/mjg >> # kdump >> -559038242 Events dropped. >> kdump: bogus length 0xdeadc0de >> >> I don't have time to look into it this week though. I have committed the patch (that was attached to a previous email) to main, since bz@ confirmed via email that it fixed the ktrace problem for him. >Possibly related: core dumps are no longer working for me on NFS >mounts. I get a 0 byte foo.core instead of a valid core dump. If core dumps still fail for a main with the patch, please let us know, so we can investigate further. Thanks and sorry for the breakage, rick -- John Baldwin
Re: ktrace on NFSroot failing?
Rick Macklem wrote: > John Baldwin wrote: > > On 3/10/22 8:14 AM, Mateusz Guzik wrote: > > > On 3/10/22, Bjoern A. Zeeb wrote: > > >> Hi, > > >> > > >> I am having a weird issue with ktrace on an nfsroot machine: > > >> > > >> root:/tmp # ktrace sleep 1 > > >> root:/tmp # kdump > > >> -559038242 Events dropped. > > >> kdump: bogus length 0xdeadc0de > > >> > > >> Anyone seen something like this before? > > >> > > > > > > I just did a quick check and it definitely fails on nfs mounts: > > > # ktrace pwd > > > /root/mjg > > > # kdump > > > -559038242 Events dropped. > > > kdump: bogus length 0xdeadc0de > > > > > > I don't have time to look into it this week though. > > > > Possibly related: core dumps are no longer working for me on NFS > > mounts. I get a 0 byte foo.core instead of a valid core dump. > I just tried a core dump for a kernel built from main sources as of > to-day and it worked ok. > > However my userland is several months old and I can't easily upgrade > it for now. > > There was a recent ZFS problem that found its way into 13.0-p8 that > I'm pretty sure is fixed now. If you had a fairly recent server exporting > ZFS, that *might* explain it? > > In particular, an NFSroot uses NFSv3 and nothing has changed for > NFSv3 in a looonnggg time. Oops, I did make a change that affected NFSv3 as well as NFSv4. Last December I committed a path to head that made IO_APPEND writes use nfs_directio_write() and avoid the buffer cache. Turns out nfs_directio_write() only worked for UIO_USERSPACE. The attached trivial patch fixes ktrace for me. I have no idea if core dumping ever does IO_APPEND VOP_WRITE()s? Please test the attached patch. Thanks, rick rick -- John Baldwin ktrace.patch Description: ktrace.patch
Re: ktrace on NFSroot failing?
John Baldwin wrote: > On 3/10/22 8:14 AM, Mateusz Guzik wrote: > > On 3/10/22, Bjoern A. Zeeb wrote: > >> Hi, > >> > >> I am having a weird issue with ktrace on an nfsroot machine: > >> > >> root:/tmp # ktrace sleep 1 > >> root:/tmp # kdump > >> -559038242 Events dropped. > >> kdump: bogus length 0xdeadc0de > >> > >> Anyone seen something like this before? > >> > > > > I just did a quick check and it definitely fails on nfs mounts: > > # ktrace pwd > > /root/mjg > > # kdump > > -559038242 Events dropped. > > kdump: bogus length 0xdeadc0de > > > > I don't have time to look into it this week though. > > Possibly related: core dumps are no longer working for me on NFS > mounts. I get a 0 byte foo.core instead of a valid core dump. I just tried a core dump for a kernel built from main sources as of to-day and it worked ok. However my userland is several months old and I can't easily upgrade it for now. There was a recent ZFS problem that found its way into 13.0-p8 that I'm pretty sure is fixed now. If you had a fairly recent server exporting ZFS, that *might* explain it? In particular, an NFSroot uses NFSv3 and nothing has changed for NFSv3 in a looonnggg time. rick -- John Baldwin
Re: ktrace on NFSroot failing?
On 3/10/22 8:14 AM, Mateusz Guzik wrote: On 3/10/22, Bjoern A. Zeeb wrote: Hi, I am having a weird issue with ktrace on an nfsroot machine: root:/tmp # ktrace sleep 1 root:/tmp # kdump -559038242 Events dropped. kdump: bogus length 0xdeadc0de Anyone seen something like this before? I just did a quick check and it definitely fails on nfs mounts: # ktrace pwd /root/mjg # kdump -559038242 Events dropped. kdump: bogus length 0xdeadc0de I don't have time to look into it this week though. Possibly related: core dumps are no longer working for me on NFS mounts. I get a 0 byte foo.core instead of a valid core dump. -- John Baldwin
Re: ktrace on NFSroot failing?
On 3/10/22, Bjoern A. Zeeb wrote: > Hi, > > I am having a weird issue with ktrace on an nfsroot machine: > > root:/tmp # ktrace sleep 1 > root:/tmp # kdump > -559038242 Events dropped. > kdump: bogus length 0xdeadc0de > > Anyone seen something like this before? > I just did a quick check and it definitely fails on nfs mounts: # ktrace pwd /root/mjg # kdump -559038242 Events dropped. kdump: bogus length 0xdeadc0de I don't have time to look into it this week though. > -- > Bjoern A. Zeeb r15:7 > > -- Mateusz Guzik
ktrace on NFSroot failing?
Hi, I am having a weird issue with ktrace on an nfsroot machine: root:/tmp # ktrace sleep 1 root:/tmp # kdump -559038242 Events dropped. kdump: bogus length 0xdeadc0de Anyone seen something like this before? -- Bjoern A. Zeeb r15:7
